Fluid pressure motor



Sept. 20, 1949. .1. w. RUSH ETAL FLUID PRES-SURE MOTOR v zNl/ENTRS Jhn WRUSh Arthur J Bent Inl/1i "111111111,

Original Filed Aug. 3l, 1944 ATTORNEY the central flange 32 of the diaphragm between the two followers. A coil type regulating spring 36 arranged in coaxial relation with the diaphragm andpower piston means 30 is contained in chamber 8 and Vis supported at onev endA on the casing wall 4 while its opposite Yend bears against the diaphragm follower 35. This spring which extends into chamber 8 .within the regulating springr35. Extending through the boss 38 and slidably mounted therein in coaxial relation with the piston means 30 and diaphragm 5 is an operating rod 39. One end of the rod 39 projects into chamber I6 at one side of the'power piston means 30, while the opposite end is disposed in chamber 3. The boss 38 is provided with an annular chamer 40 encircling the rod 39 and connected by a passagev 4I'to Vchamber I1 formed between the two piston heads I3 and I4. A choke or restriction 42 is provided in the passage 4I for limiting the rate of ow of fluid under pressure to chamber I1 and out of said chamber, as will be later described. At opposite ends of the chamber 49 the boss 38 and wall 4 are providedwith grooves containing rings 43 having sealing land sliding contact with rod 39 for preventing leakage of fluid under pressure from said chamber.

In the end of that portion of the rod 39 which is disposed in chamber 8 there is'provided a semispherical socket in which is vdisposed a ball-like end 44 of a link 45, said endV 44 vbeing secured in said socket by a member 46 secured to the end of rod 39 by a nut 41. The link 45 Vhas at its opposite end a ball-like structure 48 which is seated in a socket in the end of the diaphragm follower stud 34, and which is secured to said stud by a member 49 urged into contact with the balllikeend by a flange 50 projecting from the diaph'ragmV follower 35. Projecting from the diaphragm follower 33 into a bore in cover 2r is a member 5I having at its endaball-like structure '52 ofV larger diameter than said member and in substantial contact with the wall of said bore. The ball and socket connectionsbetween the :opposite ends' of link 45 and the operating rod 39 and diaphragm follower 33, and between the cover 2 and ball-like end 52 at the end of member 5I are provided to allow the diaphragm 5 to freely rock or tilt relative to member 39 in a direction or directions which will rock theaxis. of the diaphragm, in order that the diaphragm may freely adjust itself to the regulating spring 36 without causing binding of the operating rod 39 within the boss 38. This structure is adapted to .render the diaphragm very sensitive to slight changes in pressure in control chamber 6,'and thereforelacsuch leakage of fluid under pressure between chamberV 6 at one side of the structure and chamber 54 at the .opposite side. Chamber 54 isin constant communication with. the power `chamber .I6 through a passage 55. -The linkV 4-5 isprovided with an axial passage 56,0pen .at one end toa vthe control chamber 6.V 5 .Y

The supply valve 63 is arranged in -coaxialrela'ei passage 51 in the diaphragm follower 33 and open at the opposite end to a passage 58 in the operating rod 39. Ring likel seal members 59 are provided in the ball-like ends. ofvlink 45 and have sealing and sliding contact jwith the'walls of the respective sockets for preventing leakage of fluid under pressure from these passages to chamber 8.

Passage 51 in the diaphragm follower 33 is open tocontrol chamber. 6, so that iluid under pressure Y effective in said, chamber may flow through said passage f andY passage 56 to passage 56 in the operating rod 39. VWithin boss 38 the operating rod 39 is provided withV one or more radial bores 60 connectingipassage 58 to the annular Chamber 40', whereby the. control chamber 6 and dash-pot i .chamber I1 between the piston heads I3 and I4 ofthe power piston means 33 are in constantv communication.

In the power chamber I6 the operating rod 39 is connected to and supports a valve control memberzil Ywhich has a chamber 62 containing a uid pressure supply valve 63 and a spring 64 acting Aon said valve for urging it to a closed or seatedposi-V tion in which itY is shown. in the drawing. The passage 58m operating rod 39 Vis open to chamber 62 whereby said chamber is adapted to be constantly supplied with fluid tion with the powervpiston means 36 and has a stem 65 projectingthrough a bore Vinfthe` valve control member 6I linto ya chamber 66 in thepower piston means 30. The .chamber 66 is' open .atall ra-blepin unison. y

VThe vrelease valve 61 is adapted to cooperate with a seat provided on the power pistonmeans 30 around oneend of a passage68 extending into the pistonrod 26- for thereby controlling. com-Y munication between saidpassagerandqthe power Y chamber I6. Incoverf-S an annular chamber169 is provided around thepiston rod V2li-'and is con. nected tov a uid pressure release pipe.19.i The piston'rod 26 is provided. 'with a radial=port 51 I connecting passage 68inV the rod' to the annular chamber69. Beyondeach of vthe'opposite ends of chamber 69'the cover 3,carries a ring'seal member 12 having sealing and sliding contact Awith said rod to prevent leakagewof'fluid under pressure from chamber 69 12o-atmosphere. 4. A y

The radial release port 1I is of relatively small areaconstituting in effect a lchoke for limiting the. rate of release-of fluid under" pressure from chambers 66 and I6 to a degree having -acertain relation tothe flow' capacity of choke, 42. Likepast the supply'valve63 to chambers 66 and I6 and this relation may be obtained by the supplyV `valve stem 55 reducing the 4area4 or theopening through the valvev controlmember 6 I in which said stem is disposed, v.to a degree which provides. the required choking eiectto obtain said relation. The sizeof these openings as showninthe drawingiere-.merely illustrative. 1. Y v Y 4.v.Therelease pipe 10 may leaddirectly to atV mosphere or .itmay lead-.to vanso-,called sump reserveir provided. for. .receiving uid Yunder-pres: Sure after it. haebeen ,used for effecting@ de,- sired operation. Thepressure of iuidfinigthe. sumpreservoirmw at times. exceed. thatfgf the under pressure from atmosphere, hence the use of the sealing rings 'I2'. Whether the pipe 10 leads to the atmosphere or rto a sump reservoir is however` immaterial to the present invention. A sump reservoir of the type under consideration is however shown and fully described in the copending application of' Rankin J. Bush hereinbefore referred to and, if desired, reference may be made to that application for a more complete description thereof.

The valve control member 6I is provided with an `annular collar or flange 13 for engaging the inner surface 14 of a member 15 provided in the power piston means 36, wherebyv movement of the valve control member 6I by the operating rod 39 in the direction of the casing cover 2 will pull the power piston means 3I1r to the position in which it is shown in the drawing. At the QDDO- site side of flange 13 on valve member 6l there is clearance space provided to allow movement of said valve control member relative to the power piston means 3o a distance suicient to open the supply valve 63 without said member contacting a shoulder or surface 56a in chamber 6.

It will be noted that the operating rod 39, valve control member 6I, and the supply and release valves 63 and 61, respectively, are supported by the casing wall 4, independently of the pilot means including diaphragm 5 and followers 33 and 35, and also independently of the power piston means 30, whereby said rod, member and valves will at all times be maintained in operative relation to the diaphragm 5 andwill prevent binding of said rod within the boss 38 in case of tilting of said diaphragm relative to said member or, if for any reason the power piston means 3D should tend to bindvin the bores in which itis disposed.

Operation obtained by varying the pressure through a.

range, such as seventy pounds, above the eighty pounds.

Now let it be assumed that pipe 1 and the control chamber 6 are charged with fluid at the normal pressure of eighty pounds. This pressure, effective on diaphragm 5, will move said diaphragm, the followers 35 and 33, the link 45, the operating member 39 and valve control member 6I against the opposing pressure of the regulating spring 36 to a position in which the pressure of said spring will have increased to a degree to counterbalance the pressure of fluid in chamber 6, whereupon such movement will cease. This position may be adjusted toward or away from the stop shoulder 31 in cover 2 by the use of shims 36a, as will be apparent.

Fluid at the normal pressure of eighty pounds in pipe 'I and chamber 6 will equalize through,

passage 51 in the diaphragm follower 33, passage 56 in link 45, passage 58 and ports 66 in the operating rod 39, chamber 4Q and passage 4I intothe dash-pot chamber I'I between the two piston.

heads I3 and I4. The pressure of iluid thus obtained between the two piston headsy I3 and IIIv will create a force, equal to said pressure times.

The posi.-

ject in chamber 6I tothe norma-1l pressure of eighty pounds isV preferably so adjusted by the shims 36a,1that the power piston means `3l) moving une der the pressure of fluid in the dash-.pot Achamber IT, will contact the casing wall 4 at the same time it moves: intoseating engagement with the release valve '61 and hence without opening the supply valve 63. In the drawing the parts-of the motor are shown in the positions just described, which will be assumed to be their normal posi-- tions, and with the power piston means 30 thus positioned, the lever 23 will also assume a normal position inv which it is shown in the drawing.

If the operator now desires to rock the control lever 2-3 out of its normal position in a counterclockwise direction, as viewed in the drawing, he will increase the pressure of fluid in chamber '6 throughl pipe 1 to a degree above the normall pressure of eighty pounds. This increase inpressure on diaphragm 5 will deflect saidl diaphragm against the opposing force of the regulating spring 36' to a new position in which the pressure of said spring isv increased to a degree sufficient to counterbalance the pressure ofuid in said chamber whereupon the diaphragm will cease moving. Y This deilection of diaphragm 5 will act through rod 39 to move the valve control member 6I relative to the power piston means 30, and with the release valve 31V closed holding the supply valve 63 against movement in this direction, thevalve control member 5I will move out of seating engagement with said supply valve. Fuid under pressure will, then flow from the. supply valve chamber 62. to the power' pistonchamber I6, and when the pressure of fluid 'in chamber I6 is thus increased sufliciently with respect to the opposing pressure of fluid in chamber I.1. will move the power piston means 30 in the direction of the right-hand and rock theflever, 213- in a counterclockwise direction out of its normal position After the, diaphragm 5 ceases movement in re- Sponse, to the increase in pressure of fluid in' chamber 6, the movement of the power piston means 30 by the pressure of fluid in chamber I6 will be relative to the valve control member 6I. The supply valve 63 will move with piston means 3D relative to the valve control member 6I until Said valveV seats against said valve control mem'- ber to cut-off further flow of fluid under pressure to power piston chamber I6. When the supply of fluid under pressure to chamber I6 is thus cut olf the power piston means 3,0 and lever 2 3 will stop, in a position determined by the position of the diaphragm 5 and thus by the increase in pressure of fluid in pipe 1 and control cham,` ber 6.

The pressure of fluidl required in power cham-- ber I6 to-operate the power piston means 30 andlever 23 will depend upon the resistance to movement of the device being controlled, so that at one time a relatively small increase in` pressure lin chamber I6 may be adequate to elfect such movement, while at another time or under a different conditiona greater pressure will be required in said chamber. The pipe 'I, being however charged with fluid at a pressur-e in excess. of eighty pounds, constitutes a source of fluid at adequate pressure to insure operation of the power piston Ymeans 30 to actuate lever 23 as intended.

It is desired to point out that the position to. which the power piston means 3U is moved. corresponds tothe position of the diaphragm; 5 and thus the increase in pressure in pipe 1 over the with that in the control pipe 1 by way normal pressure, and the structure provides fori obtaining fluid in chamber I6 at a pressure suicfient to lensure such positioning of the power piston means. *Y V Y If the operator now desiresA to 'cause rocking of theV lever 23 to a greater degree from itsi normal position, he will increase the pressurein pipe 1 and diaphragm chamber 6 to a degreelcorresponding to the desired new position of leverA 23, and the motor will again operate inthe same manner as above described, to move said lever and then stop it in the new position, which V position again corresponds, to the position of `diaphragm 5.

It will now be apparent that the lever 23 can` beV moved out of its normal position shown, toy any other desired position, by providing'rfiuidatl the proper pressur-eV in control pipe 1 anddiaphragm chamber 6. This movement may be made in steps, if desired, or in a single step, according to the degree of increase in pressure in pipe 1 and chamber 6. When a maximum pressure of uid is provided in pipe 1V and chamber 6, deecting the diaphragm 3| against the' opposing force of the diaphragm regulating spring 36 to a maximum degree, the lever 273 will be movedto a maximum extent away from its normal position, as will also be apparent. i

The movement of Vthe powerV piston means 30 as above kdescribed is opposed at all times by pressure of uid in the Vdash-pot chamber I1, which is in constant communication with the control pipe 1 through the choke 42. l It will thus.

pipe 1 since movement of the piston head I4 by 40 pressure of fluid inchamber I6 will reduce the Volume of chamber I1 and choke 42 will restrict outow of fluid under pressure from said chamber, the degree of such increase depending upon and varying in proportion to the rate of move ment of the power piston means 30 by` pressure of fluid in chamber I6. If the rate of movement of the power piston means is relatively slow there may be substantially no increase in pressure in chamber I1 incident to the restricting effect of choke 42, however, if the piston means 3Il`tends to jump or move rapidly upon supply of uid to the power chamber I6, the pressure in chamber I1 will suddenly increase to such a degree `asV to effectively dampen and reduce the rate of movement of said piston means. This damping effect acting in conjunction with the limited or re stricted rate of supply of uid under pressure to the power piston chamber I6 by way of the vsupply valve will then cause the power piston means` 30'to positively stop assoon as the supply'valve 63 seats, and hence in a'position corresponding to the position of diaphragm and thejpressure of iluid in the control pipe 1, as abovedescribed. As soonY as the power pistonmeans 3D Vceases moving, the pressure in chamber I1 will equalize of choke 42, as will be apparent. i

If the operator now desires to rock the lever 23 back toward its normal Vposition he will reduce the pressure of iiuid in pipe 1 and diaphragm chamber 6. The regulating spring 36 willthen act to move` the diaphragm V5 to a position', in which the pressure of said spring is counterbal` anocdby thereducedpressure of Afluid in chamber 6, whereupon the diaphragm will cease movV- ing. This'movementof the diaphragm and therevby of the operating rod 39 and valve control member6| Vwill be relative to thepower piston 5 means 30, and with the supply valve 63 seated, said valve will draw the releaseY valve'61 away from its seat. Fluid under pressure will then be released from the power piston chamber I6 pastv ment, this movement of the power piston means will be relative to the Valve control member '6I and to the release valve 61 until theV seat for the release valve moves into engagement herewith to prevent further release of fluid under pressure from chamber I6 in a position of the power piston means corresponding to the position of the diaphragm l5i, and thus corresponding to ,thej'dee gree of reduction in pressure in the control pipe 1,. The power pistonrmeans 30 will stop in this position Afor reasons which will be later described. This movement of thel power Vpiston means 30 will move the lever 23 back toward Vits normal position; but said lever will stop out of its normal position in a position'determfined by the reduc-` tion in pressure in chamber 1 and the position of diaphragm 5, aswill be apparent. f'In case the operator desires to return the lever V23 Yfurther in the direction of its normalp'ositionhe will effect Ya further reduction in pressure of fluid iii-control pipe 1 and in diaphragm chamber 6 and themotor will again'operate las' above described to correspondingly change the position of lever 23, as will be apparent. Upon reducing the pressure of fluid in pipe 1 and chamber 6 to the'r normal degree of eighty pounds, the lever 23 will be returned to its normal position as will also be apparent.. It will thus be seenthat the operator can cause 5 the lever 23 to be returned toward its normal positionV and to be stopped in any selected position out of normal position by reducing the pressure of fluid inthe control pipe 'I to the proper degree. Such return. movement of lever 23 may be made in any` desired number of stops or may be continuous, according to theV pressure change in pipe 1 as will beY seen. Y Y Y When the pressure of fluid in pipe 1 is reduced to effect return movement of lever 23, the pressure of fluid in chamber I1 will also tend to correspondingly reduce by flow throughchoke 42. Howeverfas the power piston means moves toward its' normal Vposition it willv increase the volume of chambery l1 and the choke means 42 is effective.' in case the power piston ,means 30 tends to move rtoo'rapidly or to -jump toward its normal posi*- tion, to sorestrict inflow of fluidr pressure 'from' control pipe 1 to said chamber, Athat the Ypressure'in said chamber will reduce Vbelow that in the control pipe to a degree proportional to the rate ofsuch movement. "This reduction in pressur'e in chamber I1 will reduce the vforce onpis-Y Y ton means 30 tending toreturn it to its normal position and this action plus the limited or con-Q trolled rate of Y release of fluid under pressure from chamber 'I6 by wayhof the relativelyV small release port 1I is effective to stopthe power pi ton means immediately upon obtaining Va pol sition corresponding to that of the diaphragm, .75 and in which the release va1ve761 seftts.Y

It 'will now be seen that due to the Vuse of choke :'42, chamber I1 acts -in eilectv like a 'dash-pot, and 'it has beenA determined that this structure effectively prevents the piston means 30 from overtraveling a .position corresponding to the pressure of fluid in the control pipe 1, and hence the position 'ofthe control 'er pilot diaphragm 5. This is very important, for in case the power piston means 33 were moving in response to an increase in pressure in chamber l6 and overtraveled, the release valve4 61 would be opened and reduce the pressure of fluid in chamber I6, as a result of which., the direction of movement of the piston means would tend to reversel and close the release valve and reopen the supply valve 63, due towhich the piston means would tend to again move in the original direction, resulting in what is known as pumping. Such action might even occur 'on reducing the pressure of fluid in the pipe 1 as above described. It has, however, been found that the dash-pot structure using control pipe pressure in the dash-pot chamber I1 and choke 42, plus the restricting means for limiting the rates of supply and release of fluid under pressure to and from chamber I6 eiectively prevents pumping and renders the power piston means 3D stable and accurate in adjustment. Moreover this structure permits the desired prompt change in position of lever 23 in response to a change in pressure in the control pipe 1.

In the above described operation it will be noted that pressure of lluid in the power chamber I6 acting on the operating rod 39 is opposed and offset by the same pressure of fluid acting in chamber 54 on the ball-like structure 52, so as to have no effect upon the controlling pressure in chamber 6 acting on diaphragm 5.

In case of failure of the supply of iiuid pressure on an airplane, as to pipe 1, it is desirable that the different controlling devices on the engine automatically operate to insure continued operation of the engine at an adequate speed to maintain the airplane in the air. The motor above described and shown in Fig. 1 of the drawing may be employed for controlling the richness or temperature of the fuel mixture to the engine, and in case of loss of the supply of controlling fluid pressure to pipe 1, it is desirable that the controlling lever 23 be automatically moved back to its normal position, in which it is shown in the drawing, to provide a rich fuel mixture to the engine or a fuel at a temperature which will insure against freezing of moisture in the fuel supply line.

This automatic return of lever 23 to its normal position is obtained in case of loss of the supply of fluid pressure to the control pipe 1 and diaphragm chamber 6 by means of the regulating spring Sii. It will be seen that if the pressure of uid in chamber 6 is lost, the spring 36 acting through link 45 and rod 39 will move flange 13 on the valve control member 6I into engagement with surface 'l on member 15. This will open the release valve 61 to release any fluid under pressure in chamber I6 and will then pull the piston means su to its normal position in which it is shown in the drawing, at which time the follower 33 secured to diaphragm 5 will substantially contact the stop shoulder 31 in the cover. It will be noted that with the parts of the motor in their normal positions, as shown in the drawing, the clearance space between the diaphragm follower 33 and shoulder 31 equals substantially the space between the flange 13 on valve control member 6l and surface 14 on the member 15 secured to the power piston means 30, whereby the above described positioning of the power piston means Y3l) willl be assured in case of loss of fluid pressurein the control pipe 1`.

Summary From the `above description it will now be seen that the ball and socket connections between the opposite ends 'of link '45 and the diaphragm 5 and member 3'9 renders said diaphragm effective to move said' member longitudinally in either one direction or in the opposite directi'on for controlling operation of the valve control Vmember 6l and valves 63 and 61to control the pressure 'offl'uid lon the power lpiston 30. This Vconnection is provided to permit deflection 'of diaphragm "5 relative to member 39 in any direction which 'would' rock the axis vof said diaphragm relative to that of said member so that said diaphragm may readily adjust itself to changes in pressure of lluid in chamber 6 without causing member 39 to bind in the wall 4. As a result, the member 39 will be accurately positioned in accordance with even slight changes in controlling pressure in chamber 6 to in turn cause operation of valve 63 or 51 to effect a corresponding change in pressure in chamber I6 for adjusting the power piston 30. The pipe 1 constitutes both a control pipe for diaphragm 5 and a source of fluid under pressure to control operation of the power piston 30, and the link l5 and ball and socket connections at its opposite ends constitute structure for conveying uid under pressure from said pipe to the supply valve chamber 62 to so control said power piston.

For the purpose intended, the fluid motor is relatively small, compact, light in weight and for the reasons just described, is sensitive to even slight variations in controlling pressure so as to be positive and accurate in adjustment in accordance with such changes in pressure.

Having now described our invention, what we claim as new as desire to secure by Letters Patent, is:

1. A lluid motor comprising a casing, an axially movable member disposed in said casing, means supporting said member against sidewise movement, valve means in said casing arranged for` control by said member and operable upon movement of said member in one direction to supply fluid under pressure from one chamber to another chamber, flexible diaphragm means disposed in said casing in coaxial relation with ysaid member, strut ymeans connecting said diaphragm means and member, said diaphragm means being deilectable by lluid under pressure supplied to a third chamber to move said member in said one direction, said strut means comprising a link, and ball and socket-like means connecting opposite ends of said link to, respectively, said diaphragm means and member, said diaphragm means, link and member having cooperating passages provided a fluid pressure supply communication to said one chamber from said third chamber.

2. A uid motor comprising a casing, a member slidably mounted in a bore in said casing, a flexible diaphragm for operating said member secured around its edge in said casing and comprising a universally movable central portion, an element associated with said central portion for movement therewith, and strut means operatively connecting said member to said element for movement therewith, said` strut means and element comprising interconnecting universal joint operating means.

3. A fluid motor comprising a casing, a meming and comprising a/universally movable central portion, a bore in said casing at each of the opposite sides vof said diaphragm and in coaxial relation therewith, follower means secured to said central position of said diaphragm comprisningn amemb'e projecting from' one'side of said `diaphragm and havingv an enlarged spherical like end portion disposed to slide in one of said bores, a member slidablymounted inthe other bore, a strut, and ball and socket universaljoi-nt means operativelyfconnecting,opposite ends of said strut to respectively said member and follower means.- A JOHN W. RUSH.

ARTHUR. J. BENT.

Y REFERENCES CITED The following references are Vof le ,of this patenti' UNITED-STATES PA'I'EIN'I'S Y K Number Name Date 573,213 Fuller Dec. 15,1896 1,233,856

Vrecord ln the Y Elder July 17, 1917 

